Members of the polyomavirus family, Polyomaviridae, infect mammals (rodents, bovines, primates/humans) and birds (fowl, psittacines) and can severely affect various organs in these subjects. So far, ten human polyomaviruses have been described. Two of these, JC-polyomavirus (JCPyV or JCV) and BK-polyomavirus (BKPyV or BKV) are established pathogens which are known to cause severe disease in humans. For example, in immunosuppressed subjects, lytic infection of oligodendrocytes by JCV results in the fatal demyelinating disease, progressive multifocal leukoencephalopathy (PML). BKV infection in immunosuppressed subjects results in kidney necrosis and polyomavirus-induced neuropathy (PVN). Two other closely-related polyomaviruses, KI-polyomavirus (KIPyV or KIV; Karolinska Institute) and WU-polyomavirus (WUPyV or WUV; Washington University), discovered almost simultaneously in 2007, have been isolated from respiratory secretions and may be associated with respiratory tract infection. See, e.g., Allander et al., J. of Virol. (2007) 81: 4130-6; Gaynor et al., PLoS Pathogens (2007) 3: e64. Merkel cell polyomavirus (MCPyV or MCV), discovered in 2008, has been found to be integrated in a large proportion of Merkel cell carcinomas of the skin. See, e.g., Feng et al., Science (2008) 319: 1096-100. In 2010, three new skin infecting polyomaviruses, HPyV6, HPyV7, and trichodysplasia spinulosa-associated polyomavirus (TSPyV or TSV), were discovered. See, e.g., Schowalter et al., Cell Host Microbe (2010) 7:509-515; Meijden et al., PLoS Pathogens (2010) 6:e1001024. For example, TSV was discovered in proliferative skin lesions (trichodysplasia spinulosa) seen in immunosuppressed patients. Meijden in supra. In March 2011, a ninth polyoma virus HPyV9, related to a monkey lymphotropic virus (LPV), was cultured from the blood of immunosuppressed patients. See, e.g., Trusch et al., J. Gen. Virol. (2012) 93:698-705. Most recently, in 2012, a new polyoma virus was reported isolated from the stool of a healthy child from Malawi. See, e.g., Siebrasse et al., J. Virol. “Identification of MW polyomavirus, a novel polyomavirus in human stool” 86:10321-10326.
Polyomaviruses, such as JCV and BKV, are a highly common source of childhood and young adult infection. A large majority of these infections appear to cause little or no symptoms and are probably lifelong persistent among almost all adults. Diseases caused by polyomavirus infections are most common among subjects who become immunosuppressed due to AIDS or old age, or after organ transplantation. Unfortunately, effective vaccines or antiviral therapies targeting these viruses do not currently exist. Thus, there remains a need for therapies to treat and prevent viral infections such as polyomavirus infections.